The primary goal of this project is to monitor global gene expression patterns in response to viral pathogenesis in the shrimp, Litopenaeus stylirostris. Changes in gene expression patterns have profound effects on biological functions. Increasingly, focused researched efforts are emerging to understand invertebrate defense systems and host response to pathogens. The innate immune strategies developed within invertebrate systems serve as models for understanding host defense strategies in response to viral pathogens for both vertebrates and invertebrates. To date, there are limited reports in penaeids using expression analysis to discover genes involved in the innate immune system and only one that has partially examined global gene expression. There are two techniques available for global gene expression analysis, cDNA microarray and serial analysis of gene expression (SAGE). Both are aimed at monitoring thousands of genes within a biological system under different experimental conditions, however, SAGE is the only technique that does not require prior knowledge of the genome of interest. In addition, SAGE analysis is based on the direct numerical counting of gene tags for comparison between libraries, rather than the arduous statistical methods required for microarray fluorophore signal intensity analysis. With this in mind, the objectives of this research are three-fold: 1) to compare global gene expression profiles between virally infected and healthy shrimp using SAGE, 2) to further characterize differentially expressed SAGE tags between healthy control (pathogen-free) versus virally infected shrimp using generation of longer cDNA fragments (GLGI) and 5' rapid amplification of cDNA ends (RACE), and 3) to determine expression levels of the differentially expressed genes for varying time points. The fulfillment of these objectives represents a unique opportunity to understand the invertebrate immune system as it relates to viral pathogenesis and will serve as a model to understand other animal, vertebrate and invertebrate, defense mechanisms. The primary goal of this project is to monitor global gene expression patterns in response to viral pathogenesis in the shrimp, Litopenaeus stylirostris. Increasingly, focused researched efforts are emerging to understand invertebrate defense systems and host response to pathogens. This project represents a unique opportunity to understand the invertebrate immune system as it relates to viral pathogenesis and will serve as a model to understand other animal, vertebrate and invertebrate, defense mechanisms. [unreadable] [unreadable] [unreadable]